With the development of technology, touch panels have become more and more widely used. The touch panel provides a simple and convenient manner of human-computer interaction by replacing a mechanical button panel with a tactile feedback system. According to different combinations of the touch panel and the display structure, the touch panel can be divided into types of Add-on, On-Cell and In-Cell. The In-Cell touch screen has a touch electrode of the touch panel embedded in the display structure, which can reduce the overall thickness of the module, and can reduce the manufacturing cost of the touch screen, and thus has a significant advantage in the market.
The In-Cell touch panel utilizes the principle of mutual-capacitance or self-capacitance to detect a touch position of a finger. For example, a plurality of self-capacitance electrodes disposed on the same layer and insulated from each other can be disposed in the touch panel. When the human body does not touch the screen, capacitance of the respective self-capacitance electrodes is a fixed value. When the human body touches the screen, capacitance of a corresponding self-capacitance electrode is a value resultant from adding the human body capacitance on the fixed value. The touch detection chip determines the touch position by detecting a change in the capacitance value of each self-capacitance electrode during the touch period. Compared with the mutual-capacitance touch screen, the self-capacitance touch screen can effectively improve the signal-to-noise ratio of the touch signal, thereby improving the accuracy of the touch detection.